After installing the Intel C++ Composer XE 2011 Update 5 the integration of Microsoft* Visual Studio 2010* or Visual Studio 2008* does not work anymore. There are different kind of error messages like the one below showing up:

There are also errors indicating that the files IntelCppOptPkg.dll or IntelLibOptPkg.dll are missing. It's not possible to use the Intel C++ compiler within Visual Studio.

Root Cause : An older beta package was likely installed on the system. The beta package contains higher version number so when installing the newer product update with lower version number the installation could not cleanly uninstall the beta. And at the end the IDE integration module contains a mismatched files.

Note: it is difficult to install an older product on top of a new project correctly.